Such a laser catheter for bypass surgery is known from EP 750,476. This document describes the use in the ELANA (Excimer Laser Assisted Non-occlusive Anastomosis) operating technique. This Elana technique was developed by neurosurgeon C. A. F. Tulleken. For the Elana technique, one requires an Elana catheter and an Elana ring, which are jointly called Elana Arteriotomy System.
The catheter disclosed in EP 750,476 is used for performing an ETS-anastomosis (ETS=End To Side) between a graft vessel and a target vessel. The graft is fixed with an end to the side of the target vessel, while the blood flow through the target vessel, also called recipient vessel, is not interrupted, i.e. blood continues to flow through the target vessel while performing the anastomosis. For this purpose, first the graft vessel is fixed to the target vessel and subsequently, after this fixation is established, the flow connection between the target vessel and graft vessel is made by removing the part of the wall of the target vessel which lies in front of the fixed end of the graft vessel. Said part of the wall of the target vessel is removed by means of an tubular arrangement of optical fibres emitting a tubular bundle of laser light beams originating from the fibres and a suction gripper provided inside the tubular arrangement of optical fibres. The tubular bundle of laser light beams burns a circle into the wall of the target vessel, resulting in a circular passage connecting the lumens of the graft vessel and target vessel. The circular wall part of the target vessel—i.e. the part lying inside said burned circle—is gripped by the suction gripper and removed together with the withdrawal of the catheter after the burning operation. The distal ends of the optical fibres of this known laser catheter define a circle extending in a plane essentially perpendicular to the longitudinal axis of the catheter. During use the laser catheter extends perpendicular to the target vessel, resulting in a perpendicular ETS-anastomosis with a circular passage between the graft vessel and target vessel. In order to ensure a complete cutting away of tissue along the said circle, the teaching is that the cutting laser light beams should impinge on the target vessel as perpendicular as possible. This in order to avoid scattering of the laser light beams by inter alia reflection effects, which would maker the cutting action less effective and less reliable. A perpendicular impinging from the laser light beams further keeps the required depth of tissue to be burned away as short as possible. For example, in case the laser beams impinge at about 45° on the wall of the target vessel, the depth of tissue to be burned away is about 40% more than in case the laser beams impinge perpendicular.
There are however also applications, for example in the field of cardiovascular surgery but also in the field of surgery of intracranial arteries, in which a slanting ETS-anastomosis is desired or required. In a slanting ETS-anastomosis define the graft vessel and target vessel an angle different from 90°, in general in the range of 30°-60°.